1. Field of the Invention
The present invention relates to a serial printer comprising a printing head loaded on a carriage, in which the carriage is moved in the horizontal direction to move the printing head loaded on the carriage in the horizontal direction for effecting the printing operation.
2. Description of the Prior Art
A conventional serial printer will now be described.
A carriage loaded with a printing head is connected to a part of a toothed belt or wire rope, and by moving this toothed belt or wire rope, the movement of the carriage is accomplished. According to another method, a screw shaft engaged with the carriage is pierced through the carriage and this screw shaft is rotated by a motor to move the carriage.
In the conventional apparatus, since a toothed belt or wire rope or a screw shaft is interposed between the carriage and the driving power source, that is, the motor as power transmitting means for effecting the movement of the carriage, the following disadvantages arise.
(1) Since the driving power of the motor does not act directly on the carriage, the power loss of the motor is inevitably caused.
(2) Because of stretching or deformation of the toothed belt or wire rope or the screw shaft as power transmitting means, the inertia of the carriage changes and a deviation is caused in the precision of the movement or positioning.
(3) Since the construction of parts is complicated, the assembling operation is very difficult and troublesome, and a large space is necessary for packaging the parts, with the result that it is very difficult to reduce the manufacturing cost and diminish the size of the apparatus.